Upper bearing lubrication for outboard gearcase

ABSTRACT

An arrangement for lubricating the upper bearing for a drive shaft in a marine propulsion drive shaft housing. In accordance with the invention, the drive shaft below the bearing is housed in a cavity which has a cross-sectional dimension only slightly greater than that necessary to afford rotation of the shaft. The cavity is provided with oil so that the cavity is only partially full when the shaft is not rotating, and the shaft is formed, below the bearing, with a noncircular cross section so that shaft rotation raises the level of the oil in the cavity and communicates the oil with the lower bearing.

United States Patent Holtermann 51 Feb. 29, 1972 [54] UPPER BEARING LUBRICATION FOR OUTBOARD GEARCASE [211 App]. No.: 19,050

2,440,338 4/1948 Kincannon ..184/6.l8

Primary Examiner-Manuel A. Antonakas Attorney-Robert K. Gerling, Robert E. Clemency, John W. Michael, Gerrit D. Foster, Bayard H. Michael, Paul R. Puemer, Joseph A. Gemignani, Andrew 0. Riteris and Spencer B. Michael [57] ABSTRACT An arrangement for lubricating the upper bearing for a drive shaft in a marine propulsion drive shaft housing. In accordance with the invention, the drive shaft below the bearing is housed in a cavity which has a cross-sectional dimension only slightly greater than that necessary to afford rotation of the shaft. The cavity is provided with oil so that the cavity is only partially full when the shaft is not rotating, and the shaft is formed, below the bearing, with a noncircular cross section so that shaft rotation raises the level of the oil in the cavity and communicates the oil with the lower bearing.

4 Claims, 3 Drawing Figures UPPER BEARING LUBRICATION FOR OUTBOARD GEARCASE BACKGROUND OF THE INVENTION The invention relates generally to marine propulsion devices, such as outboard motors and stem drive units, and more particularly lower units therefor, which lower units are, in normal use, at least partially in the water and which are conventionally vertically tiltable and horizontally swingable to afford steering. Such marine propulsion units commonly include an upright drive shaft which is supported by upper and lower bearings in a drive shaft housing and which drives a propeller shaft mounted in bearings in a gear housing connected to the bottom of the drive shaft housing. More particularly, the invention relates to supplying lubrication to the bearings supporting the drive shaft in the drive shaft housing, and still more particularly to supplying lubrication to the upper bearing located in spaced relation above the bottom of the drive shaft housing.

SUMMARY OF THE INVENTION The invention provides an arrangement for lubricating an upper drive shaft supporting bearing in a marine propulsion unit, which bearing is usually not physically located in oil. In accordance with the invention, the drive shaft is housed in a cavity which is only a little larger in cross-sectional dimension than is necessary to afford unhindered rotation of the drive shaft. In addition, the drive shaft, below the upper bearing and within the cavity just mentioned, is provided with a noncircular cross section. Also in accordance with the invention, lubricating oil is provided in the cavity so that when the drive shaft is not rotating the cavity is only partially full. However, rotation of the drive shaft tends to create a wall of oil having an inside cylindrical diameter equal to the maximum crosssectional dimension of the shaft. As a consequence, the oil level in the cavity rises and thereby supplies lubricant to the upper bearing.

The principal object of the invention is to provide an arrangement for providing lubrication to an upper drive shaft bearing.

Other objects and advantages of the invention will become known by reference to the following description and accompanying drawings in which:

DRAWINGS FIG. 1 is a fragmentary view, partially in cross section, of a marine propulsion unit in accordance with the invention.

FIG. 2 is a fragmentary view, partially in cross section, of another marine propulsion unit in accordance with the invention.

FIG. 3 is a fragmentary enlarged sectional view taken along line 33 of FIG. 1.

DETAILED DESCRIPTION Shown in the drawings is a marine propulsion lower unit 11 which can be part of an outboard motor or a stern drive and which is supported for vertical tilting and horizontal swinging as is well known and conventional in the art. The lower unit 11 includes a drive shaft housing or drive shaft housing portion 13 and a gearcase or gearcase portion 17 which is connected to the lower end of the drive shaft housing.

The drive shaft housing 13 includes a sleeve or sleeve portion 19 defining a cavity 21 and the gearcase also includes wall means defining a cavity 23 which can be in communication with the drive shaft housing cavity 21. Supported by upper and lower bearings 27 and 29, respectively, which are located in the cavity 21 of the drive shaft housing 13 and which are spaced apart at a distance, in one specific embodiment, of 6 inches, is a drive shaft 31 which extends through both bearings 27 and 29. At its lower end, the drive shaft 31 has mounted thereon a bevel gear 33 forming a part of a drive connection 37 with a propeller shaft 39 which is rotatably supported in the gearcase cavity by means of spaced bearings 41 and 43.

The drive connection 37 between the drive shaft 31 and propeller shaft 39 can constitute either a bevel gear (not shown) fixed to the propeller shaft 39 and in mesh with the bevel gear 33 or a dog clutch such as is commonly used in stem drives and outboard motors and which commonly includes a dog which is nonrotatably mounted on the propeller shaft 39 and selectively engageable with a pair of bevel gears 49 rotatably mounted on the propeller shaft 39 and in mesh with the bevel gear 33. At its upper end, the drive shaft is operably connected to a suitable source of power, such as an engine. As thus far described, the construction is entirely conventional.

In accordance with the invention, the cavity 21 in the drive shaft housing 13, between the upper and lower bearings 27 and 29, is only of such dimension as will afford unrestricted or unhindered rotation of the drive shaft 31. Also in accordance with the invention, the drive shaft 31, in the area between the upper and lower bearings 27 and 29, has a noncircular crosssectional dimension. In one specific embodiment as shown in FIG. 3, the drive shaft 31 includes a hexagonal portion approximately 6 inches in length between the upper and lower bearings and with a cross-sectional area with a dimension A" of 0.715 across the corners, while the cavity 21 has a circular cross section between the upper and lower bearings 27 and 29 with a diameter of 0.725 inches.

Also in accordance with the invention, the cavity 21 is supplied with oil so that, when the drive shaft 31 is not rotating, the cavity is only partially filled.

Also in accordance with the invention, means are provided for supplying the lower unit 11 with the before-mentioned oil 59. In this regard, the drive shaft housing 13 is provided with a.

hole 53 which is normally closed by a plug but which can be used to fill the cavity 21 in the drive shaft housing 13 and, if the drive shaft housing cavity 21 communicates with the gearcase cavity 23 to fill both cavities. In addition, the hole 53 also serves to establish the normal level of the oil in the unit 11 when the shaft 21 is not rotating. As indicated above, it should be noted that it is within the purview of the invention for the cavities 21 and 23 in the drive shaft housing 13 and the gearcase 17 to be in communication with each other. It is further to be understood that the housings 13 and 17 are sealed to prevent loss of oil from the cavities 21 and 23 to the surrounding environment.

If desired, the drive shaft 31 can also be provided (as shown in FIG. 2) with a slight twist to assist in raising the oil 59 and thereby placing the oil in communication with the upper bearing. In other respects, the construction shown in FIG. 2 is the same as that of FIG. 1.

Although other arrangements can be employed, in the disclosed construction, a cap 63 is shown retaining the upper bearing in position in the drive shaft housing.

In use, rotation of the radially outermost portions or comers 67 (see FIG. 3) of the drive shaft 31' tends to create a void within the area through which the outermost portions 67 of the drive shaft 21 rotate and to displace the oil radially outwardly and upwardly with an inner cylindrical wall having a diameter equal to the maximum cross-sectional dimension A" of the shaft 21. Oil thus displaced from adjacent to the outer surfaces of the drive shaft in response to drive shaft rotation, rises and comes into lubricating communication with the upper bearing 27. If the area in the cavity 21 available outwardly of the area of rotation of the radially outermost portions 67 of the drive shaft 21 is less than the amount of oil located within the area of rotation when the shaft is not rotating, then portions of the oil will be carried around with the shaft 21 within the area of rotation.

Thus, there is disclosed an effective arrangement, operable upon shaft rotation, to supply oil from the cavity 21 to the upper bearing 27 Various features of the invention are set forth in the following claims.

What is claimed is:

1. A marine propulsion unit including a drive shaft housing having an interior cavity, an upper bearing in said drive shaft housing and a drive shaft supported in said cavity, at least in part, by said upper bearing and having, below said upper bearing, a noncircular cross-sectional area with its greatest radial dimension slightly less than that which would afford free rotation of said drive shaft in said cavity, and a quantity of oil such as would partially fill said cavity when said drive shaft is not rotating and such as to rise into communication with said upper bearing upon drive shaft rotation.

2. A marine propulsion unit in accordance with claim 1 wherein said drive shaft is twisted in the area below said upper bearing.

3. A marine propulsion unit in accordance with claim 1 including a hole in said drive shaft housing for filling said cavity and establishing the level of oil in said cavity when said shaft is not rotating.

4. A marine propulsion unit including a drive shaft housing having an interior cavity, an upper bearing in said drive shaft housing, and a drive shaft supported in said cavity, at least in part, by said upper bearing and having, below said upper bearing, a noncircular cross-sectional area with its greatest radial dimension slightly less than that which would afford free rotation of said drive shaft in said cavity to thereby provide a pumping action in response to drive shaft rotation, whereby, when the cavity is partially filled with oil, shaft rotation will cause such oil to rise in the cavity for lubrication of the upper bearing.

* i II! I 

1. A marine propulsion unit including a drive shaft housing having an interior cavity, an upper bearing in said drive shaft housing and a drive shaft supported in said cavity, at least in part, by said upper bearing and having, below said upper bearing, a noncircular cross-sectional area with its greatest radial dimension slightly less than that which would afford free rotation of said drive shaft in said cavity, and a quantity of oil such as would partially fill said cavity when said drive shaft is not rotating and such as to rise into communication with said upper bearing upon drive shaft rotation.
 2. A marine propulsion unit in accordance with claim 1 wherein said drive shaft is twisted in the area below said upper bearing.
 3. A marine propulsion unit in accordance with claim 1 including a hole in said drive shaft housing for filling said cavity and establishing the level of oil in said cavity when said shaft is not rotating.
 4. A marine propulsion unit including a drive shaft housing having an interior cavity, an upper bearing in said drive shaft housing, and a drive shaft supported in said cavity, at least in part, by said upper bearing and having, below said upper bearing, a noncircular cross-sectional area with its greatest radial dimension slightly less than that which would afford free rotation of said drive shaft in said cavity to thereby provide a pumping action in response to drive shaft rotation, whereby, when the cavity is partially filled with oil, shaft rotation will cause such oil to rise in the cavity for lubrication of the upper bearing. 